Apparatus for case-hardening, &amp;c.



A. w. MACHLET.

APPARATUS FOR CASE HARDENING, 8L0.

APPLICATION FILED .IUNE 29, 1918.

Patented Apr. 20, 1920.

4 SHEETSSHEET 1.

I wuewbw W Q/M A. W. MACHLET.

APPARATUS FOR CASE HARDENING, 6m.

Patented Apr. 20, 1920.

4 SHEETS-SHEET 2.

APPLICATION FILED JUNE 29.1918.

A. W. MACHLET.

APPARATUS FOR CASE HARDENING, &c.

, APPLICATION FILED JUNE 29, I918- 1,337,24--1. Patented Apr. 20, 1920.

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' Wanna I A. W. MACHLET.

APPARATUS FOR CASE HARDENING, (kc.

APPLICATION FILED JUNE 29, 1918.

1,337,244. Patented Apr. 20, 1920.

4 SHEETS-SHEET 4.

.92 If F 7.5 94 v @vwwtoz UNITED STATES PATENT. OFFICE.

ADOLPH'W. MACHLET, 0F ELIZABETH, NEW JERSEY.

ArrAnA'rUs FOR CASE-HABDENING, 6w.

Be it known'that I, AnoLrH W. MAoHnn'r, a citizen of the United States,residing in Elizabeth, in the county of Union and State of New Jersey,have invented certain new and useful Improvements in Apparatus forCase-Hardening, &c., of which the following is a specification.

Certain features of this invention relate to case-hardening machines ofthe type disclosed in the patents granted to me No.

822,460 dated June 5, 1906, No. 847,588, dated March19, 1907, No.884,180, dated April 7, 1908, No. 884,181, dated April 7, 1908, and No.961,305, dated June 14, 1910, in which steel or other ar ticles to becasehardened are placed in a retort, through which a current ofcarburizing gas flows while the retort is maintained at a carburiz- .ingheat and kept in motion to agitate the articles. Several features of theinvention may be used for other purposes than casehardening, especiallywhere it is desired to bring metal articles to a high heat, withprovision for rapidly discharging and re- One feature of the inventionrelates to the construction of a closed retort, whether used for theabovementioned or other purposes.

In the apparatus disclosed in said patents, after the case-hardening ofthe articles was completed, the cover or lid at one end of the retortwas removed, and the articles were raked 'or pulled out, and a freshbatch of articles pushed into the retort. These operations consumedconsiderable time, keeping down the. earning power of the apparatus.Moreover, considerable waste of heat from the furnace was entailed,owing to the duration ofthe discharging and recharging op erations.

According to certain of the present improvements, the operations ofdischarging and recharging are very quickly and readily performed, thusincreasing the efiiciency of the apparatus and substantially reducingthe loss of heatfrom the furnace.

To eflect a ready discharge, the retort is carried in a manner to becapable of dipping or swin ing downwardly at its discharge end. heinterval between removing the cover (for discharging and recharging theretort) and replacing the same, is so shortened, that the flames withinthe furnace may in some cases advantageously be kept Specification ofLetters Patent.

Patented Apr. 20, 1920'.

1918. Serial No. 242,622.

going full blast during the discharging and recharging operations, andthe retort may also be kept in rotation; the supply of carburlzing gasbeing of course shut off before the removal of the cover, to be turnedon again as soon as the cover is replaced upon the retort.

The same device which depresses one end of the furnace to discharge theretort, may be reversed to bring the furnace not only back up tohorizontal working position, but also to elevate farther the dischargeend of the retort, and depress its other end, thus facilitating andexpediting the recharging of the retort, which hence can be very quicklyaccomplished.

Suitable flexible connections are provided between the furnace and thesupply for mixed air and fuel going to the flame-chamber, theseconnections permitting the upand-down swinging of the furnace; andanother fiexible connection may be provided for supplying thecarburizing gas to the end of the retort opposite its discharge end.

Taking up now the improvements in retort construction, it has been foundin practice that a revolving retort in which articles are case-hardenedor treated, is subject in the course of time to distortion and otherdeleterious changes, due to the alternate heating and cooling thereof,especially for carburizing purposes; the carburizing or other gas beingapt to combine with the iron of which the retort is made. It has beenfound that the retort, if made of cast iron, gradually and permanentlyexpands in diameter. Moreover, the cast iron retort gradually increasesin length, and is apt to become distorted in the course of time, someparts thereof slowly increasing in dimensions out of proportion to otherports. If the retort ismade of steel, it may gradually shrink indiameter; and owing to the formation of scale, the body of the retort isapt to grow thinner after long use.

Accordingly, among the objects of my invention are these, to effect areduction in the escape of heat from the ends of the furnace, especiallythe end thereof which is avoid the necessity of replacing the same; andI further aim to increase the load-car-' rying capacity of the retortwhen heated, to

avoid the necessity of fitting .it up with a 6 partition at the endopposite from its discharge end, to reduce the cost of maintenance, toreduce the consumption of heating gas and carburizing gas; and generallyto lower the cost of carburizing or heat-treating metal articles.

One of the means for substantially reducing the loss of heat from thefurnace, is to reduce the diameter of that portion of the retort whichprojects through oneof the ends of the furnace to rest upon the exteriorend of the furnace; said projecting hub car-' rying a wheel which maysupport the retort upon the usual exterior rolls mounted upon the endsof the furnace; a sprocket or other gear-Wheel being also connected tothis projecting hub for revolving the retort; and a supply ofcarbonizing or other gas being introduced throughthis tubular hub intothe interior of the retort.

In order to permit the construction of the retort in the just-describedform, and avoid liability of collapse of a long-used retort at the highheat which is necessary in carbonizing, I employ an alloy of nickel,chrome and iron, or nichrome, this alloy being usually about 60% ofnickel, 20 or 30% of chrome, and 10 or 20% of iron. The retort,

with its end and projecting hub, is cast in a single piece of nichrome,and, notwithstanding the small diameter of said projecting hub, (whichof course at its inner portion becomes highly heated) is well able tosupport the load of the retort and of a heavy charge of articlestherein. Moreover, this retort is heat-resisting, and is well adapted towithstand much higher heats than would be the case with steel tubing, orwith caststeel or cast-iron; wherebya substantial advantage is gained inthe carbonizing operation. The new retort, moreover, does notpermanently expand, and hence does not outgrow its clearances, as is aptto be'the case with a retort which is made from a steel tubing; andhence the original fitting of the retort to the furnace may bemade muchcloser, since no room needs to be allowed for the permanent expansion ofthe retort. It results that a great and continuous loss of heat throughthe clearances or crevices around the ends of the retort is saved; thisbeing in addition to the substantial closing up by fire-brick of one endof the furnace, which has heretofore not been found possible. Moreover,the retort is highly durable and practically indestructible. It isobvious that this retort may be made in other forms, while retainingmany or all of the advantages above set forth, and also that it may beused in other than tilting furnaces.

Another feature of the present invention resides in means forcontrolling the heat of different portions of the retort. One advantagegained is that more heat may be supplied to the ends of the retort thanto the 30 middle portion thereof, thereby to compensate for the tendencyof heat to escape from the ends of the retort more rapidly than from themiddle thereof; and hence the retort may be maintained at substantiallyuni- 35 form heat throughout its length. Or, when desired, the middlemay be heated more than the end portions. Where a single large articleis to be case-hardened or heat-treated only at one portion thereof, thesame may 0 be inserted in the retort, and the desired portion thereofmay be heated, other portions of the retort, and hence of the work, notbeing heated. In this way, for example, one portion of a large shaft maybe casehardened or treated, while another portion or portions may notbe. Or several long shafts may be inserted together into the retort, andtheir ends only maybe case-hardened, by usingonly the end manifolds.Another advantage gained is that the capacity of the retort may bevaried. When desired,

the inner head which is attached to the cover and forms one end of theretort proper, may.

be adjusted along the retort so as to shorten the chamber which containsthe articles to be carburized; and only such shortened portion needs tobe heated, this being permitted by the use of the aforementioned devicefor regulating the heat of the various portions of the retort. By meansof this improvement, several variations may be made in the capacity ofthe retort.

To carry: out the heat-regulating feature ofv the invention, suitablemanifolds are placed along the furnace, and each is provided with anindependent supply of mixed air and fuel, so-that each manifold may becut out of use, whereby as much of the length of the retort may beheated as desired, without the necessity of consuming gas for heatingthe portion of the retort which it is not desired to heat.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a perspective elevation of a carburizing machine embodyingthe present improvements in one form.

Fig. 1 shows an assortment of stems for 130 bevel pinion 37 at lowspeed.

is settable to vary the effective length of the retort.

Fig. 2 is a perspective illustrating the machine from its opposite end.

Fig. 3 is a part-sectional side elevation of the machine, showing theretort, however, in the form of a steel tube projecting from both endsof the furnace, since certain of my improvements can be used withvarious kinds of retorts.

Fig. 4 is an end elevation of the machine showing the discharge endthereof.

Fig. 5 is a detail plan of certain retortdriving connections.

Fig. 6 is an elevation of the machine taken at the end opposite fromFig. 4.

Fig. 7 is a part-sectional view illustrating the preferred form ofretort and furnace-end.

Fig. 8 is an enlarged detail of a hook for securing the cover upon theretort.

The furnace is illustrated in the form of a cylindrical horizontalbarrel 1O suspended between its heads or ends 12, 13 by means ofgudgeons or trunnions 14 projecting from flanges or brackets 15 onopposite sides of the furnace and mounted in bearings 16 on the tops ofstandards 17 which may be connected at their lower portions by across-tie 18. This furnace has a complete interior cylindrical linin 19of fire brick or other refractory material, as well as similar disks orannular linings 20, 21 for its rear and front heads 13 and 12; saidheads having central openings 22, 23 through which extend, at Fig. 3,projecting ends 24, '25 of a' cylindrical or tubular retort 26.

The retort is revolubly supported by means of its projecting endseXteriorly-of.

the furnace upon pairs of rolls 27, 28; the retort having at one endflanges 29 forming a groove in which the rolls run to prevent endwisedisplacement of the retort, thus preventing it from falling when tiltedup or down.

An annular space is left between the retort and the cylindrical liningof the furnace to form a flame chamber 30; and the retort is providedwith spacing disks forming ends or heads 31, 32 which are confinedwithin the ends of said flame chamber 30, and comprise disks 33 ofasbestos or other refractory material, each confined between metaldisks. The burners 34 within the flame chamber are seen at the top ofthe furnace at Fig. 3.

For keeping the retort in rotation during the cementation of thearticles, as well as during the tilting of the furnace, power may bederived from a motor or other source through a hain belt 35 running overa sprocket wheel 36 which drives a concentric If said belt is driven athigh speed, a speed-reducing mechanism may be provided in a casing 38;and a suitable clutch 38 for starting and stopping the rotation of theretort may be mounted upon the shaft 39 of the pinion 37 and controlledthrough a handle 40. Said bevel pinion 37 meshes with another bevelpinion 41 provided upon one end of a shaft 42 which extendslongitudinally of the furnace, and carries at its other end a sprocketwheel 43 connected by a chain 44 to a larger sprocket wheel 45, which isfixed upon one end of the retort, whereby the latter is revolved slowly.Said longitudinal shaft 42 is supported at one end in a bearing 46 inprojections provided upon the furnace head 13, the other end of shaft 42having a bearing in a box or bracket 47 connected to a furnace trunnion;and hence all these gears may swing with the furnace as the' latterturns upon its trunnions. The axis of the sprocket wheel 36, which isconnected to the source of power, is concentric with the axis of thefurnace trunnions or gudgeons, and thus the tilting of the furnace doesnot disconnect the bevel pinions 37, 41, and so the retort may remain inrotation during the tilting of the furnace, which is a convenience indischarging the retort, and favors a comparatively cool part of thefurnace, all

the remaining portion of the retort-rotating train operating slowly, andnot liable to faulty operation by reason of the high heat.

Carburizing gas is supplied to the retort through a pipe 48 which may beof flexible metallic construction, to accommodate the tilting of thefurnace, said flexible pipe 48 connected with the upper end of avertical pipe 49 whose lower end is connected by a gland 50 to an inletpipe 51 which extends through the end of the retort and also through itsinner partition or head 31, Fig. 3, to supply the retort with gas. Theupper end of said pipe 49 may be loosely confined between supports 52projecting horizontally from the head 13 of the furnace, and united 'attheir outer ends by cross-pins 53, Fig. 2 which confine the pipe 49, sothat said pipe is prevented from substantial displacement in anydirection, but still is allowed a certain amount of play. at its upperend, to accommodate displacements due to heating and cooling of theretort. or to other reasons.

At its opposite end, the retort has an ex-- te'rior cover or lid 54,which is provided with pivoted sliding hooks 55 catching over a flange56 which surrounds and is rigid with the projecting end portion of theretort said hooks being drawn tight, thus securing the cover, by meansof wing nuts 57. Each hook has at one end a tooth to hook over theflange 56, and at the other a stem 58, upon .which' the nut 57 isthreaded. The hook has between its ends a longitudinal slot 59,

whereby it is pivotally carried upon a pin 60, which crosses the housing61 in which the hook slides and turns, and upon which the wing nut 57bears.

This cover 54 is joined by a pipe 62 to the .interior head 32 of theretort, so that the interior head 32 will be, pulled off with saidcover. Said pipe 62 also serves as a vent, to

. permit the vitiated carburizing gas to escape from the retort; saidgas being usually supplied to the retort under low pressure. The end ofthe pipe 62 projects from the cover 54 (see Fig. 1), and may serve as acon- 'venience upon which to attach a long bar or handle for use inremoving the cover; or where the cover is of large size and heavy,

the same may be manipulated by means of a fall and tackle, if desired. Aregulating valve 63, Fig. 3, may be provided upon vent pipe 62, ifdesired.

Air and gas are separately supplied to the 4 apparatus through pipeswhich are flexible Then the hooks 55 are cau ht over the flange- 56 andthe wing nuts 5 tightened. Gas

n and air may be admitted to the furnace and ignited at a small outlet64 provided in a plug 65 which closes a hole in the end 12 of-thefurnace just above the discharge end of the retort; said opening alsoserving as a peep hole for inspection of the interior of the furnace.Then, by manipulating the handle 40, the clutch is thrown into use whichstarts the operation of the gears and chain which rotate the retort. Theretort is brought up to carburizing heat, and the heat is maintaineduntil the articles are cemented. Thereupon, the supply of carthe retort.

burizing gas is cut off from the retort by closing a valve 66, Fig. 2,and the wing nuts 57 are turned to release the hooks 55, which arewithdrawn from the flange 56. Then the cover 54 is pulled off, togetherwith the inner head 32, which is thus removed from Then a hand-wheel 67is employed to rotate a shaft 68 mounted in bearings 69 upon the mainframe of the machine, and having a worm 70 which engages a worm-wheel orsegment 71 mounted upon the furnace barrel, thereby tilting said barrelupon its trunnions from normal level position to depress the open end ofthe retort and discharge the articles therefrom to asuitable receptacle.The retort is selfdischarging when depressed. Thereupon by using thehand-wheel 67 the worm shaft is rotated backwardly to tilt up thefurnace; this operation continuing until the open end of the retort iselevated in the opposite direction, 11. e., above horizontal position,to facilitate recharging at the same end. After a fresh batch ofarticles is inserted, the cover 54 with its head 32 may be restored, andthe hand-wheel 67 may then be employed to restore the furnace tohorizontal position. During these operations, the flames continue toplay around the retort, so that it is kept at carburizing heat, wherebythe freshly inserted articles are quickly brought up to carburizingheat; the supply of carburizing gas 'being again turned on. Thehorizontal position of the retort may be conveniently ascertained bymeans of a gage or index 71 mounted on the framework to coincide with aplate 71 onthe furnace.

At Fig. 7 the retort is seen in the form of a casting 72 of nichrome,the casting including an end 7 3within the flame chamber of the furnace,thereby permitting this end of-the furnace to be substantially closed bya fire-brick structure or disk 74 of refractory material; a smallcentral opening 75 being left in said disk for the projectiontherethrough of a hub 76 cast upon' the retort; said opening 75 being sosmall that the loss of heat therethrough is much reduced as comparedwith .former constructions; and the end 73 of the retort also serving asa bafile to interfere with the direct radiation of heat from the body ofthe flame chamber through said opening. There may be secured upon theouter end of the hub 76 a wheel 77, having flanges 78 with anintervening cylindrical periphery to rest upon the rolls 27 seen at Fig.6, whereby the retort is revolubly supported and also prevented fromfall-ing at the tilting operation, or from otherwise moving endwise.This wheel 77 may be held on the hub 76 by a key 79, and,may also havethereon the sprocket 45 over which runs the driving chain 44 thatrevolves the retort.

The hub 76 may be hollow or provided with a longitudinal central opening80, making a tubularhub for the introduction of carburizing gas into theretort; said carburizing gas being supplied through stationary pipe 49and gland 50, the latter permitting the retort to rotate while connectedwith said stationary pipe 49. Said gland may be attached by a flange tothe hub of wheel 77, which is attached to hub 76. It will be seen thatthe hollow hub 76 is of relatively small diameter, and that it is alsocast within the barrel, to aid in agitating the articles, and permit thebarrel to be heavily charged without incurring liability of the articlesslipping around the interior periphery of the barrel.

The distribution of the mixed fuel and gas may be effected by thefollowing means; although it will be understood that this portion of myimprovements may be used with other furnaces, whether tilting or not;and it will be further understood that the tilting of the furnace may beused to advantage in connection with other means of supplying fuelthereto.

There are illustrated two short end mani folds 81, each comprising twoburners 34, and one long middle manifold 82, comprising four burners.These manifolds and burners are duplicated on the opposite sides of thefurnace. The opposite short manifolds 81 at each end of the furnace areconnected by an individual pipe 83, which may be of U-form; and thelarge middle manifolds 82 are connected by another pipe 84. A mixture ofair and gas is conducted to each of the pipes 83, 84 through anindividual connection 85, which receives compressed air from anindividual supply pipe 86 and gas from a supply pipe 87, the point ofmixture of the gas and air being at the junction of pipe 87 withconnection 85, and the control of each being determined by valves 88 and89 in pipes 86 and 87. Each of the three cross-pipes 83 is independentlysupplied with gas and air in the same manner; a main air supply pipe 90being branched to supply the three .pipes 86, and the main gas supplypipe 91 being likewise divided into branches; and each branch may haveits independent valve 88 or 89, so that air and gas of the desiredmixture may be supplied to each cross-pipe 83, 84 independently of theother cross-pipes, whereby any manifold may be either working orsilenced, as desired. The pipes 90 and 91 may be of flexible metallicconstruction, to accommodate the tilting of the furnace.

At Fig. 1 is illustrated a set of pipes 62, 62 'and 62 of assortedlengths, one (62) being the length seen in the other views, and another(62) being of a length to bring the head'32 to a position to shorten theretort chamber to an extent suitable when the front manifolds 81 are cutout; the third pipe (62) being longer, to be used when both the frontsmall manifolds 81 and the long manifolds 82 are cutout.

As seen at Figs. 3 and 7, the furnace may have one or more clean-outholes 92 in its bottom portion, each hole normally closed by means of anunderlying brick 93, which is supported by a metal plate 94, the latterbeing set up on studs 95 pendent from the bottom of the furnace andthreaded at their lower ends to receive supporting wing-nuts 96. Byturning down the nuts, the plate may be removed, together with theclosing brick, giving access to the interior of the furnace.

Variations may be resorted to within the scope of my invention, andportions of the improvements may be used without others.

Having thus described my invention, 1 claim:

1. The combination of a closed retort, a furnace having a flame chamberwithin .which the retort is supported, said retort having at one end amovable closure, and means for supporting the furnace for movement todepress the retort for discharging the same, said retort beingselfdischarging by reason of such depression thereof.

2. The combination with a closed revoluble retort, having an opening inone end through which the retort is both charged and discharged, and aclosure for said opening, of a furnace having a flame chamber withinwhich said retort is supported, said furnace mounted for a tiltingmovement to discharge. the retort, which is self-discharging when sotilted.

3. The combination with a revoluble closed retort, Having an opening inone end through which the retort is both charged and discharged, and aclosure for said opening, of i retort during the depressing andelevating movements.

4. The combination with a revoluble retort, of a tiltable furnace havinga flame chamber within which said retort is supported, said furnacemounted for a depressing movement below normal to incline the retort inone direction to discharge the retort at one end thereof, and for anelevating movement above normal to incline the retort in the oppositedirection to facilitate charging the retort at the same end, and meansfor rotating said retort within said furnace while the same, isstationary and also during the tilting of the retort in both directions.

5. The oombination'with a revoluble retort, of a furnace having a flamechamber within which said retort is supported, said furnace mounted fora tilting movement in opposite directions tocnarge and discharge theretort at the same end thereof, means for rotating said retort, saidrotating means including a gear on the end of the retort opposite fromits charging and discharging end, and a train of driving connectionsextending from said gear to about the axis of the tilting movement ofthe furnace.

6. The combination with a revoluble re tort, of a furnace having a flamechamber within which said retort is supported, said furnace mounted fora tilting movement to discharge the retort, means for rotating saidretort, said rotating means including a gear on an end of the retort, atrain of driving connections extending from said gear to about the axisof the tilting movement of the furnace, said train including a sprocketchain running over said gear, a sprocket wheel over which said chainruns, a shaft extending toward the axis of tilting movement of thefurnace, and driving gearing at about said center of the tiltingmovement.

7. The combination with a revoluble retort, of a furnace having a flamechamber within which said retort is supported, said furnace mounted fora tilting movement to discharge the retort, means for rotating saidretort, said rotating means including a gear on an end of the retort, atrain of driving connections extending from said gear to about, the axisof the tilting movement of the furnace, said train including a sprocketchain running over said gear, a sprocket wheel over which said chainruns, a shaft extending toward the axis of tilting movement of thefurnace, and also including a bevel pinion upon said shaft, a secondbevel pinion having an axis of rotation about concentric with the axisof tilting of said furnace, and a driving pulley for the lastmentionedbevel pinion.

8." The combination with a revoluble retort, of a furnace having a flamechamber within which said retort is supported, said furnace mounted fora tilting movement to discharge the retort, means for rotating saidretort, said rotating means including a gear on an end of the retort, atrain of driving connections extending from said gear to about the axisof the tilting movement of the furnace, said train including a sprocketchain running over said gear, a sprocket wheel over which said chainruns, a shaft extending toward the axis of tilting movement of thefurnace, and also including a bevel pinion upon said shaft, a secondbevel pinion having an axis of rotation about concentric with the axisof tilting of said furnace, and a driving pulley for the last-mentionedbevel pinion, a speed-reducing device being included between saiddriving pulley and the last-mentioned bevel pinion.

9. The combination with a retort, of a furnace having a flame chamberwithin which said retort is mounted, said furnace mounted for tiltingmovement to depress said re tort for dischargin the same, burners beingprovided in said furnace, and connections from said burners to a sourceof supply, said connections including members which are flexible toaccommodate the tilting of the furnace, said members arranged above thefurnace.

10. The combination of a furnace mounted to tilt and having a] flamechamber, a retort suspended within said flame chamber, and means forsupplying metal-treating gas into one end of said retort, said supplyingmeans including a member which is flexible to accommodate the tiltingmovement of the furnace and retort, said retort having a vent at a pointremote from said supply.

11. The combination of a furnace having a flame chamber, a retortsuspended within said flame chamber, and means for supplyingmetal-treating gas to one end of said retort, said supplying meansincluding a flexible member, said retort having a cover at the endopposite from said supply, and said furnace mounted to depress the endof said retort aving said cover below normal horizontal position whileelevating the opposite end, to discharge the retort when the cover isremoved, and to elevate said discharge end while depressing the otherend below horizontal, to facilitate recharging.

12. The combination of a furnace in cumbent position and having a flamechamber, a

closed retort extending through-the flame chamber and projecting at itsends from the furnace, supporting means for said retort upon theexterior of the furnace, means connected to said retort at one of itsprojecting ends for revolving the same in all positions to which thefurnace is tilted, means for supporting the furnace between its ends fora tilting movement, and means for supplying gas to said retort in allpositions thereof.

13. The combination of a furnace in cumbent position and having a. flamechamber, a retort extending through the flame chamber and projecting atits ends from the furnace, supporting means for said retort upon theexterior of the furnace, means connected to said retort at one of itsprojecting ends for revolving the same in all positions to which thefurnace is tilted, means for supporting the furnace between its ends fora tilting movement, flexible connections for fuel extending to saidfurnace, and a flexible connection for metaLtreating gas extending tosaid retort.

14. The combination of a furnace having a cylindrical flame chamber, astandard or support, trunnions whereby said furnace is mounted betweenits ends upon said support for tilting either up or down from horizontalposition, acylindrical retort extending through said flame chamber andprojecting at its ends from said furnace, supporting means for saidretort exterior to said furnace, means connected to a projecting part ofsaid retort for revolving the same, said revolving means extending to apoint about concentric With said trunnions and capable of rotating theretort in all positions of the furnace, a flexible connection to one endof said retort for supplying metal-treating gas thereto, a closure atthe other end of said retort for permitting the same to be dischargedand recharged, and means connected to said furnace for supplying fuelthereto.

15. The combination of a furnace having a flame chamber, a retortsupported Within said flame chamber, groups of burners in said furnace,means for supplying a mixture of air and fuel to each group, and meansfor closing the supply to each group independently of the remaininggroup or groups.

16. The combination of a furnace having a flame chamber, a retortsupported in said flame chamber, groups of burners on opposite sides ofthe furnace, the groups on one side being paired with the groups on theopposite side, means for supplying mixed air and fuel to each pair ofgroups independently of the other pair or pairs, and means for cuttingout any pair or pairs of the groups.

17. The combinationof a furnace having a flame chamber, a retortsupported in said flame chamber, groups of burners on opposite sides ofthe furnace, the groups on one side being separate from one another andpaired with the groups on the opposite side, means for supplying mixedair and fuel to each pair of groups independently of the other pair orpairs, and means for cutting out any pair or pairs of the groups, meansbeing provided for reducing the capacity of the retort at will byshortening the work chamber therein, whereby a portion or portions oftheretort may be put out of use and the burners for heating such portionmay be cut out.

18. The combination with a furnace having a flame chamber and a retortmounted therein, of groups of burners upon opposite sides of the furnaceto discharge within said flame chamber, the groups upon one side be ingseparate from one another and paired with those upon the other side,means affording an open communication between. the groups of each pairindependently of the other pairs, means for supplying mixed air and gasto said communicating means and means for cutting ofl the supply fromany pair or pairs of the groups.

19. The combination of a furnace having a flame chamber, a retortmounted within said flame chamber. groups of burners upon opposite sidesof the furnace, the groups upon one side being separate from one anotherand paired with those upon the opposite side, independentcross-connections for the paired groups, a supply for gas, a supply forair, branches from each of said supplies to said independentcross-connections, and means for controlling the flow of each of saidbranches independently of the others.

20. The combination of a furnace having a flame chamber, a retortmounted within said flame chamber, groups of burners upon opposite sidesof the furnace, the groups upon one side being separate from one anotherand paired with those upon the opposite side, independentcross-connections for the paired groups, a supply for gas, a supply forair, branches from each of said supplies to said independentcross-connections, and means for controlling theflow of each of saidbranches independently of the others, said furnace mounted for a tiltingmovement, and said air and gas supplies being flexible to accommodatesaid tilting movement.

21. The combination of a furnace having a flame chamber therein, aretort within said flame chamber, independent manifolds upon each sideof the furnace, each manifold comprising a group of burners, themanifolds upon one side being paired with those upon the other side, asupply for gas, a supply for air, means for mixing and distributing theair and gas to each pair of. manifolds, and means for independentlycontrolling each pair of manifolds independently of. the

others.

22. The combination with a furnace having a flame chamber therein, of aretort within said flame chamber, and selective means for heating eithera portion or all of said retort at will, means being provided forsubstantially shortening the work chamber within the retort.

23. The combination with a closed retort, of means for revolving,heating and tilting down one end of the retort to discharge the same,and tilting up the same end of the retort for re-charging the same, saidend having a removable closure.

24. The combination with a furnace having a flame chamber, of acarburizing rctort in said flame chamber, comprising a casting of theherein-described nichrome. said retort extending through the ends of thefurnace, and means upon the exterior of the furnace for supporting theretort for revolution, said furnace ends having openings fitted to saidretortwithout allowance for permanent expansion of the latter.

25. The combination with a furnace having a flame chamber, of a retortin said flame chamber, comprising a casting of the means upon theexterior of the furnace for supporting the retort for revolution, saldfurnace substantially closed at one end and having an opening smallerthan the body of the retort, and the retort closed within the flamechamber and having a hollow hub portion of reduced diameter extendingthrough the end of the furnace and supported for revolution upon theexterior of the furnace, and a supply for gas to pass through saidhollow hub.

26. The combination with a furnace having a flame chamber, of a retortin said flame chamber, comprising a casting of the herein-describednichrome, said retort extending through the ends of the furnace, meansupon the exterior of the furnace for' supporting the retort forrevolution, said furnace substantially closed at one end and having anopening smaller than the body of the retort, and the retort closedwithin the flame chamber and having a hollow hub portion of reduceddiameter extending through the end of the furnace and supported forrevolution upon the exterior of the furnace, a supply for gas to passthrough said hollow hub, a wheel carried exteriorly of the furnace bysaid hollow hub, and rolls upon which said wheel is supported.

27. The combination with a furnace having a flame chamber, of a retortin said I flame chamber, comprising a casting of the herein-describednichrome, said retort extending through the ends of the furnace, meansupon the exterior of the furnace for.

supporting the retort for revolution, said furnace. substantially closedat one end and having an opening smaller than the body of the retort,and the retort closed within theflame chamber and having a hollow hubportion of reduced diameter extending through the end of the furnace andsupported for revolution upon the exterior of the furnace, a supply forgas to pass through said hollow hub, a wheel carried exteriorly of thefurnace by said hollow hub, and rolls upon which said wheel issupported, a driving gear being also carried upon said projecting hollowhub.

28. A revoluble closed carburizing retort in the form of a tubular bodyof the hereindescribed nichrome, and having a reduced hollow hub portionat one end to pass through an opening in the furnace of less diameterthan the body of the retort, and a cover or lid at the opposite end, andalso having a supporting wheel on said hollow hub.

29. A revoluble closed carburizing retort in the form of a tubular bodyof the hereindescribed nichrome, and having a reduced hollow hub portionat one end, to pass through an opening in the furnace of less diameterthan the body of the retort, a cover or lid at the opposite end, andalso having a supporting wheel on said hollow hub, and a driving gear onsaid hollow hub.

30. The combination with a furnace having separate manifolds forsupplying fuel thereto, of a .retort having a removable coverand'mounted in said furnace, a head settable for determining thecapacity of the work chamber in said retort, an assortment of stemswhereby said head may be connected to said cover at different distancestherefrom, and means for cutting out a manifold so as to heat the retortto an extent appropriate to the position of said head.

31. The combination with a furnace and burners for supplying fuelthereto, of a retort in said furnace, provision being made forregulating the effective length of said retort, and means for cuttingout certain of said burners, so that the furnace may be heated by theremaining burners to an extent appropriate to the effective length ofthe retort.

32. The combination with a furnace having a flamechamber and providedwith fuelsupplying means, including a series of manifolds extendingalong said chamber, of a retort mbunted in said chamber, means forvarying the effective length of said retort, and means for cutting outone or more manifolds, to enable only the effective length of the retortto be heated by the remaining manifolds.

33. The combination with a furnace provided with a succession offuel-supplying manifolds, of a retort mounted in said fur-' nace, acover for said retort, a head settable within the retort, an assortmentof stems for connecting said cover to said head at varying distances,whereby the effective length of the retort may'be varied, and means forcutting out any manifold independently of the others.

"directly exposed-to heat, so that the cover and head may be withdrawntogether from the retort, and so that the effective capacity of theretort may be substantially varied.

36. The combination with a furnace, of a succession of fuel-supplyingmanifolds extending along said furnace, the manifolds on one side pairedwith those on the opposite side of the furnace, and the manifolds ineach pair being in open com- 'munication witheach other, and means forcutting off any pair of manifolds at will.

37. The combination with a furnace, of a succession of fuel-supplyingmanifolds extending along said furnace, the manifolds on one side pairedwith those on the opposite side of the furnace, and the manifolds ineach pairbeing in open communication with each other, and means forsupplying mixed air and fuel to each manifold independently of theothers.

38. The combination with a retort having a flange, of a cover havinghooks to catch over the flange at any portion thereof, and individualmeans for drawing said hooks to hold the cover to the retort, Y

39. The combination with a retort having a flange, of a cover havingindependently movable hooks to catch over said flange. at any portionthereof, each hook capable of both. a turning movement, and rotatablemeans for tightening the hooks upon the flange to catch over the flange,and an endwise sliding movement to tighten the cover to draw the coveragainst the retort.

40. The combination with a retort having a flange, of a cover havinghousings, hooks mounted to slide in said housings, each housing having apivot pin, andeach hook being slotted to engage said pin, and

threaded means connected to the housings to draw the hooks against theflange.

41. The combination with a furnace having a flame chamber and, having atone end a large opening and at the other end a small opening, of aretort cast of the herein-described nickel alloy and comprising a barrelportion which projects through said large opening and a hub portionwhich projects through said small opening, and

exterior means upon the ends of the furmice for supporting said retortby means of said projecting portions, the dimensions of said openingsapproximating those of said casting.

42. The combination with a furnace having a flame chamber and having atone end described nickel alloy and comprising a barrel portion whichprojects through said large opening and a hub portion which pro jectsthrough said small opening, exterior means upon the ends of the furnacefor supporting said retort by means of sa d projecting portions, thedimensions of said openings approximating those of said casting, saidhub portions being hollow, and

- means being connected to supply metaltreating gas through said hollowhub;

43. A retort cast of the herein-described nickel alloy, in the form of acylindrical barrel open at one end and closed at the other end, and ahollow hub portion of reduced diameter projecting from the closed end.

44. As a new article of manufacture, a cylindrical retort in the form ofa barrel open at one end and having a head at the other end, and ahollow hub of reduced diformed of nichrome or an alloy of nickel,

chrome and iron, nickel forming the main portion of the alloy to preventthe permanent expansion of the barrel to close said openings by reasonof successive case-hardening operations in said retort.

46. A retort in the form of a cast cylinder of the herein-describednichrome, said retort comprising extensions whereby the same may besupported at the exterior of the furnace, and closed at its ends betweensaid extensions.

47. A retort in the form of a cast cylinder of the herein-describednichrome, said retort comprising extensions whereby the same may besupported at the exterior of the furnace, and closed at its ends betweensaid extensions, one of said closed ends being cast integral with saidretort, and the other closed end being removable.

48. A retort in the form of a casting of nichrome, comprising extensionswhereby the same may be supported at the exterior of the furnace, saidretort closed at one. of its ends and having a hub portion ofsubstantially reduced diameter to form one of said extensions, to permitsuch extension to pass through a hole in the furnace wall ofsubstantially less diameter than the body of theretort, and a removableclosure for the other end of the retort.

49. A retort in the form of a casting of nichrome, comprising extensionswhereby the same may be supported at the exterior of the furnace, saidretort closed at one of its ends and having a hub portion ofsubstantially reduced diameter to form one of said extensions, topermitsuch extension to pass through a hole in the furnace wall ofsubstantially less diameter than the body of the opening extending fromits outer end to the interior of said retort, to serve as a duct forcarburizing gas.

50. A revoluble carburizing retort inthe form of a tubular body ofnichrome having a closed integral end provided With an integralextension in the form of a hub of substantially less diameter than saidbody, to extend through the Wall of the furnace and permitthe opening insaid Wall to be of substantially less diameter than the body of theretort.

51. A revoluble carburizing retort in the form of a tubular body ofnichrome having a closed integral end provided with aniintegralextension in the form of a hub of substantially less diameter than saidbody, to extend through the Wall of the furnace f and permit the openingin said Wall to be of substantially less diameter than the body of theretort, said hub provided With a supporting Wheel and a driving gear,and the oppositeend of said retort having an extension to projectthrough the opposite Wall of the furnace, and also having a cover re-,

ing the heat thereof and of preserving its dimensions through anindefinite number of carburizing operations, and formed of theherein-described nichrome, said retort hav ing end portions projectingthrough the walls of the furnace and supported exteriorly of said Walls;said walls having openings through which said end portions project, saidopenings approximating the dimensions of said retort Withoutsub'stantialallowance for permanent expansion ofthe latter.

53. The combination with a furnace having a flame chamber, of a retortin said flame chamber, comprising a casting of the hereindescribednichrome, said retort extending through the ends of the furnace, andmeans upon the exteriorof the furnace for supporting the retort forrevolution, said furnace substantially closed at one end and having anopening smaller than the body of the retort, and the retort closedWithin the flame chamber and having a hub portion of ADOLPH W. MACHLET.

Witnesses:

PHILIP C. OSTERMAN, SAMUEL R. OGDEN.

